MySql 5.6 slow Creating Sort Index

So my years of Linux has started and now we are stumbling onto below issue.
This machine is a HP DL360G8 with 24 cores and 128GB reading from a HP raid5-set operating 15k SAS disks. In Hyper-v we have created a virtual machine dedicated for mysql bases on Ubuntu 14.04. The machine has access to 8 cores and 40gb ram.

Below database has 450.000 rows and measures 650MB, can anyone explain why creating the sort index takes almost a full second?

the query will run, but surely return 0 records due to this:
WHERE lcase(basepartcode)='ABC900'

anyhow, I do agree with the question: why are you using lcase() on the fields?
the issue is that indeed you need to change the db/application logic to avoid this function at that place
the typical solution would be to store the values basepartcode in lowercase, and use this query:
WHERE basepartcode =lcase('ABC900')

My bad, i'm sorry, i had to anonimize this query because it is recognizable for my customer who is a big retailer in western europe.
In the original query 'ABC900' was indeed lower case so this does not seem the issue.

According to my limited MySQL knowledge it seems that sorting is done on harddisk in stead of in memory, does this makes sence? If so, how can i change this behaviour?

When table data gets too large to manage or queries take too long to execute the solution is often to buy bigger hardware or assign more CPUs and memory resources to the machine to solve the problem. However, the best, cheapest and most effective so…

In this video, Percona Solution Engineer Dimitri Vanoverbeke discusses why you want to use at least three nodes in a database cluster.
To discuss how Percona Consulting can help with your design and architecture needs for your database and infras…

In this video, Percona Solution Engineer Rick Golba discuss how (and why) you implement high availability in a database environment.
To discuss how Percona Consulting can help with your design and architecture needs for your database and infrastr…